Three-phase separators are widely used in the petrochemical and oil and gas industries. Engineers often face the problem of designing new separators or verifying the fitness-for-service of existing separators for new service conditions that the separator was not originally designed to handle. Obtaining the smallest vessel size suitable for each service is a time consuming task, which can have a significant impact on the overall cost of projects.
One of the most common approaches to sizing three-phase separators is to use a trial and error technique that requires that the designer estimate the separator dimensions. The programs then calculate the maximum allowable velocity of each phase based on the required residence times and usual vapor-liquid separation. It is based on these allowable velocities that the programs decide whether the separator is large enough for operating conditions or design conditions. This prior art approach does not provide the optimum vessel size and requires several attempts by the user to come up with the right combination of diameter and length. Another limitation of these tools is that they mostly work based on a fixed length to diameter ratio.